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Brake pedal feel


Aztec62

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Hello all,

now that the brake system is back in order on my Reatta, I have one question:

When the hydro accumulator is fully charged, I can push the brake pedal down to a metal stop.

It does not feel like on a normal brake system where I push against a brake fluid "cushion"

 

There is no air in the system, pads are new all round. Emergency brake is correctly adjusted and gets firm after 2 and a half pushes.

I can push the brake pedal about 12 times until the pump starts again.

Fluid level is OK.

 

Is this normal?

 

Henning

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Hello all,

now that the brake system is back in order on my Reatta, I have one question:

When the hydro accumulator is fully charged, I can push the brake pedal down to a metal stop.

It does not feel like on a normal brake system where I push against a brake fluid "cushion"

 

There is no air in the system, pads are new all round. Emergency brake is correctly adjusted and gets firm after 2 and a half pushes.

I can push the brake pedal about 12 times until the pump starts again.

Fluid level is OK.

 

Is this normal?

 

Henning

It sounds to me like that there is still air trapped in the system? That system is hard to purge. If my memory serves me correctly that is a diagonal system and has to be bled right rear then left front then left rear to right front. You may want to check out what I just said to see if I'm right or not.

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I have an 88.  I had the brakes bled by a shop that specializes in brakes just to make sure it was done correctly.  The brakes feel  perfect, just like my 2016 Chevrolet SUV's brakes.

Print the instructions from this site and take it to a professional.  It cost me $60 USD to have it done here in Arizona at a Just Brakes shop.  The peace of mind was well worth the cost.

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Here is the easiest way I know to bleed brakes but you will need a "helper". Get the car up on blocks [all 4 wheels] Remove wheels. Turn the key to the "on" position, open passenger rear bleeder and have helper put foot ob brake. This will cause pump to run. After air/fluid is out is out repeat for driver's rear.

Turn key off.

Do front brakes [passenger side first] in the conventional way "pumping up" the brakes, opening bleeder allowing brake pedal to travel to floor close bleeder, repeat.

Go around twice making sure you have all the air out. Also keep a close eye on the resivoir to make sure the fluid level is high.

I did it this way after replacing the rubber brake lines at thewheel and the brakes on the Black actually work better then eith of the other two Reattas.

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Here is the easiest way I know to bleed brakes but you will need a "helper". Get the car up on blocks [all 4 wheels] Remove wheels. Turn the key to the "on" position, open passenger rear bleeder and have helper put foot ob brake. This will cause pump to run. After air/fluid is out is out repeat for driver's rear.

Turn key off.

Do front brakes [passenger side first] in the conventional way "pumping up" the brakes, opening bleeder allowing brake pedal to travel to floor close bleeder, repeat.

Go around twice making sure you have all the air out. Also keep a close eye on the resivoir to make sure the fluid level is high.

I did it this way after replacing the rubber brake lines at thewheel and the brakes on the Black actually work better then eith of the other two Reattas.

 

Dave,

this is how I did it twice already. What made me think is the fact that I am unable to pump the brakes by stepping on the brake pedal several times. Normally, I can get that "cushion" feel temporarily when there is air in the system, but not this time. I can hit the brakes as much as I want, the brakes are not getting "hard". This only happens when I have done it enough times to deplete the hydraulic pressure ball. But that is not what I was looking for.

That is why I started to ask my self that it might be normal to push the brake pedal to a mechanical stop on these brake systems, but apparently, it is not. Makes sense, too now that I think of it.

So I guess I will have to do the bleeding procedure some more until all air is out.

 

Thanks folks!

Henning

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Something is not right as I went back and reread your original post. I don't know anyone who can get 12 pumps before the pump runs so there has to be air.

Are you getting good flow of brake fluid through the bleeders during the bleeding process? Maybe you have collapsed rubber brake lines.

Another thing to try, crack open the hard brake line on top of the pump/motor and depress the brake. This would ensure that all the air is out of the pump/motor.

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Something is not right as I went back and reread your original post. I don't know anyone who can get 12 pumps before the pump runs so there has to be air.

Are you getting good flow of brake fluid through the bleeders during the bleeding process? Maybe you have collapsed rubber brake lines.

Another thing to try, crack open the hard brake line on top of the pump/motor and depress the brake. This would ensure that all the air is out of the pump/motor.

 

Dave, the brake hoses are all new, so no problem here. Fluid flows freely through the bleeders. I will check again after how many brake pedal pumps the pump starts to run. Public holiday tomorrow in Germany so I will do it tomorrow.

 

 

Henning

Bremen, Germany

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Sounds good, but don't forget to try cracking open the line on top of the pump/motor. There has to be air someplace.

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I have always considered being able to press the pedal down to a hard stop to be normal. It requires more pressure than normal braking but mine has always done that. I am pretty certain my system is working properly. Pressures are spot on, healthy accumulator, new front hoses, but I can still press "through" the normal pedal movement with a long steady push. I have always been able to do this and I did so today on a run to my cottage. Brakes work perfectly.

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I have always considered being able to press the pedal down to a hard stop to be normal. It requires more pressure than normal braking but mine has always done that. I am pretty certain my system is working properly. Pressures are spot on, healthy accumulator, new front hoses, but I can still press "through" the normal pedal movement with a long steady push. I have always been able to do this and I did so today on a run to my cottage. Brakes work perfectly.

 

2seater I would suggest that you try going into a panic stop at 70 MPH and see how the system handles it. If it does, fine...great, but if not, I wouldn't want to find that out when it's to late.

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I have always considered being able to press the pedal down to a hard stop to be normal. It requires more pressure than normal braking but mine has always done that. I am pretty certain my system is working properly. Pressures are spot on, healthy accumulator, new front hoses, but I can still press "through" the normal pedal movement with a long steady push. I have always been able to do this and I did so today on a run to my cottage. Brakes work perfectly.

 

My brakes are similar to yours but the pedal doesn't ever get hard as long as the pump is running.  I just tested mine to see if the way they operate is what I remembered and it is.  When I press on the brake pedal really hard, hard enough to slide the tires on most cars, the pedal still has a little give to it. I didn't stand on the pedal with both feet because I don't want to damage anything.  I wouldn't do that under panic stops anyway. Once the ABS kicks in or the wheels start sliding you are doing all you can to stop no matter how hard you push the pedal.

 

Something I found when pressing the pedal in the garage with the pump running is this;  If I press the pedal down hard and then let up about 1/2" and press down again, the pedal will go down farther each time I do it until the pedal is almost on the floor.  It never gets hard as you describe.  The pedal will actually go down farther than it does when the pedal is hard after the accumulator has been discharged by pumping the pedal 30 times.  Try it and see if you get the same results.

 

I think my brakes are in good condition and working properly. They have allowed me to stop really quick and straight twice when a deer jumped out right in front of me.  All I had time to do was jump on the brake pedal with no pumping beforehand. I like the pedal feel on my Reatta.  The only complaint I have with my brakes is the pump starts on the second pump of the pedal.

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Hello all,

now that the brake system is back in order on my Reatta, I have one question:

When the hydro accumulator is fully charged, I can push the brake pedal down to a metal stop.

It does not feel like on a normal brake system where I push against a brake fluid "cushion"

 

There is no air in the system, pads are new all round. Emergency brake is correctly adjusted and gets firm after 2 and a half pushes.

I can push the brake pedal about 12 times until the pump starts again.

Fluid level is OK.

 

Is this normal?

 

Henning

 

Twelve pumps before the pump starts is not normal and to me it signals that you have a problem. My guess would be that the pressure switch is at fault. If switch did not pick up the brake pump relay until the pressure was way too low the brake pedal would get hard due to lack of adequate pressure in the accumulator.  I haven't heard of that before but it is possible.  To know for sure if my theory is correct you would need to put a pressure gauge on the system to see how low the pressure goes before the pump starts.

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My brakes are similar to yours but the pedal doesn't ever get hard as long as the pump is running.  I just tested mine to see if the way they operate is what I remembered and it is.  When I press on the brake pedal really hard, hard enough to slide the tires on most cars, the pedal still has a little give to it. I didn't stand on the pedal with both feet because I don't want to damage anything.  I wouldn't do that under panic stops anyway. Once the ABS kicks in or the wheels start sliding you are doing all you can to stop no matter how hard you push the pedal.

 

Something I found when pressing the pedal in the garage with the pump running is this;  If I press the pedal down hard and then let up about 1/2" and press down again, the pedal will go down farther each time I do it until the pedal is almost on the floor.  It never gets hard as you describe.  The pedal will actually go down farther than it does when the pedal is hard after the accumulator has been discharged by pumping the pedal 30 times.  Try it and see if you get the same results.

 

I think my brakes are in good condition and working properly. They have allowed me to stop really quick and straight twice when a deer jumped out right in front of me.  All I had time to do was jump on the brake pedal with no pumping beforehand. I like the pedal feel on my Reatta.  The only complaint I have with my brakes is the pump starts on the second pump of the pedal.

In my opinion I believe you guys are battling an air in the system condition. I saw a lot of Teves system problems when I was a GM Dealership mechanic. That was what really drove me to swap out the system for a vac. control system. You should not be able to work that pedal to the floor. I would think that doing a panic stop under controlled conditions and breaking something would allow you to fix it before you had to rely on it. I've been in a small number of panic stops and noticed the closer I got to an accident the harder I pushed on the pedal abs or not.  I rest more comfortably driving my car knowing of it's capabilities.  Just my opinion.

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2seater I would suggest that you try going into a panic stop at 70 MPH and see how the system handles it. If it does, fine...great, but if not, I wouldn't want to find that out when it's to late.

 

I understand and have wondered about it also, but it has always been this way in the 24 years I have owned the car. I have tried panic stops at speed on back roads and it is a revelation, in a good way. Unless you are belted in, it will be difficult to stay upright. The car will almost stand on its nose and anything loose will try to get to the front floor. I also recommend everyone try an occasional test but I think most are uncomfortable with a full on test.

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My brakes are similar to yours but the pedal doesn't ever get hard as long as the pump is running.  I just tested mine to see if the way they operate is what I remembered and it is.  When I press on the brake pedal really hard, hard enough to slide the tires on most cars, the pedal still has a little give to it. I didn't stand on the pedal with both feet because I don't want to damage anything.  I wouldn't do that under panic stops anyway. Once the ABS kicks in or the wheels start sliding you are doing all you can to stop no matter how hard you push the pedal.

 

Something I found when pressing the pedal in the garage with the pump running is this;  If I press the pedal down hard and then let up about 1/2" and press down again, the pedal will go down farther each time I do it until the pedal is almost on the floor.  It never gets hard as you describe.  The pedal will actually go down farther than it does when the pedal is hard after the accumulator has been discharged by pumping the pedal 30 times.  Try it and see if you get the same results.

 

I think my brakes are in good condition and working properly. They have allowed me to stop really quick and straight twice when a deer jumped out right in front of me.  All I had time to do was jump on the brake pedal with no pumping beforehand. I like the pedal feel on my Reatta.  The only complaint I have with my brakes is the pump starts on the second pump of the pedal.

Perhaps my wording was a little off, but it does feel like it bottoms out, not a dead pedal like when the bleeder is open. The pedal pressure required to stop or hold the car is far less, and it doesn't bleed down in any fashion sitting at a long light. I won der if this is because of the dual nature of this system. The front brakes function in a pretty ordinary way with the master cylinder piston providing the pressure but the rear uses a modulated pressure direct from the boost pump system. The pressure lights never come on while pressing the pedal below normal braking.

 

I don't know about you, but I have a hard time breaking the habit of applying the brakes multiple times while slowing down. Not really pumping the pedal, but just lightly pressing the pedal as slow down, releasing slightly and reapplying. I guess it's from when my old jalopies had less than perfect systems and drum brakes.

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Perhaps my wording was a little off, but it does feel like it bottoms out, not a dead pedal like when the bleeder is open. The pedal pressure required to stop or hold the car is far less, and it doesn't bleed down in any fashion sitting at a long light. I won der if this is because of the dual nature of this system. The front brakes function in a pretty ordinary way with the master cylinder piston providing the pressure but the rear uses a modulated pressure direct from the boost pump system. The pressure lights never come on while pressing the pedal below normal braking.

 

I don't know about you, but I have a hard time breaking the habit of applying the brakes multiple times while slowing down. Not really pumping the pedal, but just lightly pressing the pedal as slow down, releasing slightly and reapplying. I guess it's from when my old jalopies had less than perfect systems and drum brakes.

 

Same here.  I don't have a problem with the pedal bleeding down under firm foot pressure.  It's just when I press the pedal down and release a little and press down again that the pedal goes down farther each time. 

 

I've just about got myself in the habit of holding down the pedal instead of pressing and releasing frequently as we all use to do on old cars with drum brakes.  If I'm in bumper to bumper traffic I still catch myself feeling of the brakes to make sure they are there. :)

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Hello all,

here is today`s update on my Reatta brake system:

I have been bleeding the complete brake system three times including the pump and the pressure reservoir.

I did not see any air bubbles.

I am pretty certain the system is free of air.

No change though about the brake pedal feel.

What I did notice is that when I was bleeding the front brakes, I was able to push the brake pedal all the way down to the floor.

This is not possible when all bleeders are closed.

Let me explain in more detail how the brake pedal feel is when the pressure reservoir is fully charged, pump has switched off, Brake/ ABS light off:

I can push the brake pedal down against some resistance about halfway, then I can feel and hear that metal is contacting metal.

When I push the pedal down more, I do in fact have a "hard" pedal feel.  

It is different from what one would feel with a normal brake system, but when I look at all the recent replies to my thread,

there might be nothing wrong with the brake system of my Reatta.

The Teves Mk.2 system simply does have an odd brake pedal feeling, I think.

 

Number of brake pedal pushes to start pump: still 12, sometimes even more. Pump runs exactly 45 seconds to completely fill the pressure reservoir.

Sorry Dave :) 

 

Henning

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Twelve pumps is unheard of. I know you have done extensive work on your system so maybe you have found something we are all missing, but it would be most unusual. The only two things I could think of to allow this would be a difference in what you measure as a "pump" or you have more than typical capacity and pressure in the accumulator system. Hard to judge without actual pressure readings. I agree entirely with retired mechanic that an actual on road panic stop test would be a good idea, maybe 100kph or so.

 

Agree the Teves does have a different feel, but I like it after I get a feel for it. It's the only system I have ever had experience with that operates the front and rear brakes semi-independently.

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I found this information on the Autozone website for brake repairs to the Teves Mark II system. I am going to double check the FSM for the same passage:

 

"Vehicles equipped with the Anti-lock Brake System may be stopped by applying normal force to the brake pedal. Although there is no need to push the brake pedal beyond the point where it stops or holds the vehicle, applying more force causes the pedal to travel toward the floor. This extra brake travel is normal."

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